Hi can someone tell me what is the difference between the SMTPd and SMTP ?? i found that smtp is Postfix SMTP client and smtpd is Postfix SMTP server is this real ??? I found other information :
postfix/smtpd - This is typically the SMTP daemon process for handling incoming mail and routing to the appropriate internal location.
postfix/smtp - This is typically the SMTP daemon process for delivering mail out to the world.
I'm realty confused !!
The article Postfix Architecture Overview holds this information.
How Postfix receives mail
How Postfix delivers mail
It describes these composants:
Network mail enters Postfix via the smtpd(8) or qmqpd(8) servers. These servers remove the SMTP or QMQP protocol encapsulation, enforce some sanity checks to protect Postfix, and give the sender, recipients and message content to the cleanup(8) server. The smtpd(8) server can be configured to block unwanted mail, as described in the SMTPD_ACCESS_README document.
The smtp(8) client looks up a list of mail exchangers for the destination host, sorts the list by preference, and tries each server in turn until it finds a server that responds. It then encapsulates the sender, recipient and message content as required by the SMTP protocol; this includes conversion of 8-bit MIME to 7-bit encoding.
For more information about Postfix see the linked article.